1. Field of the Invention
The present invention relates to a method of testing terminals and housing of a wire harness and an apparatus therefor.
2. Description of the Related
Wire harnesses for use with automobiles include not only wires for sending signals necessary for normal driving but also wires for use with various safety circuits such as air bag. A multicontact connector uses tin-plated copper terminals to connect signals for normal driving and gold-plated copper-terminals to ensure electrical connection of safety circuits. The tin-plated terminals and gold-plated terminals are of substantially the same shape. Thus, it is difficult to check in terms of shape that the two kinds of terminal have been inserted into the right terminal cavities. Therefore, the color of plated terminals is inspected to visually identify the terminals inserted into the cavities. This type of inspection is not reliable in identifying a number of terminals. In order to solve this problem, the inventor has proposed in Japanese patent Preliminary Publication No. 6-13276 a method of reliably distinguishing between two kinds of terminals by the use of a continuity-testing device shown in FIG. 9. In this method, terminals of one kind are positioned forwardly of terminals of the other, and a continuity-testing device shown in FIG. 7 is used.
A carriage base 2 is carried on a guide rail 1 and a testing device D is fixedly mounted on the carriage base 2. A multicontact connector H under test is positioned on a connector support 3 so that the connector H opposes the testing device D. A lower terminal cavity 4 of the multicontact connector H receives a gold-plated terminal C1 and upper terminal cavity 4 receives a tin-plated terminal C2. The terminals C1 and C2 are connected to wires W1 and W2, respectively, which in turn are connected to a continuity-testing device E.
The testing device D has a switch pin d1 for identifying the terminal C1 and a switch pin d2 for identifying the terminal C2. The pins d1 and d2 oppose the terminals C1 and C2, respectively. The switch pins d1 and d2 are connected to wires W1' and W2', respectively, which are connected via the continuity-testing device E to the wires W1 and W2 to complete test circuits.
The terminals C1 and C2 have substantially the same shape and the terminal C2 is positioned a distance f=1.5 millimeters forwardly of the terminals C1, as shown in FIG. 10.
The switch pin d2 has a contact pin 8 which slidably extends through a cylindrical metal tube 7 and is biased by a spring in such a direction such as to project outwardly of the tube 7. The switch pin d1 has a contact pin 10 which slidably extends through a metal tube 9 and is biased by a spring in a direction such as to protect outwardly of the tube. The contact pin 10 causes to open a normally-closed switch incorporated therein when pushed inwardly of the metal tube 9.
When the carriage base 2 is moved a predetermined distance towards the connector H, the contact pin 8 of the switch pin d2 moves into contact with the terminal C2 if the terminal C2 has been inserted in the cavity 4a, but does not if the terminal C1 is erroneously present in the same cavity. The contact pin 10 of the switch pin d1 moves into contact with the terminal C1 if the terminal C1 has been inserted in the cavity 4b. The contact pin 10 is pushed inwardly of the metal tube 9 if the terminal C2 has been erroneously inserted in the cavity 4b, causing the normally-closed switch in the switch pin d1 to open so as to not provide continuity of the test circuit.
The aforementioned testing device permits simultaneous check of whether the proper terminal is in the proper cavity and of continuity of the circuits for proper insertion of the respective terminals C1 and C2. However, a different testing device must be used for a different arrangement of the terminal C1 and C2 even if the terminals are housed in a housing of the same design. This leads to an increased number of testing devices.
In addition to the above problems, there are some problems in identifying various models of housings. FIGS. 11A-11C show housings H1, H2, and H3, each of which is formed with a cutout surface F at different locations in the outer surface thereof though the same number of terminals are arranged in the same arrangement. In order to identify housings H1, H2, and H3 from each other, the testing devices D, D2, and D3 are formed with recesses configured to the outer surfaces of the housings H1, H2, H3.
However, the testing device D1 can receive only the housing H1 while the testing device D3 can receive both housing H1 and H2. Thus, this type of testing device cannot identify different models of housing from each other. Further, a switch for detecting a terminal fully inserted into a cavity is unable to determine whether terminals are either partially inserted or have no portion inserted.